In cache county, they now do. Didn't until 2014. I will put cats on this fall to pass emissions. Plus, the stink. A good set aftermarket high flow cats should perform fine. The factory bottleneck exhaust manifolds have got to go.

For you guys that have a pre lci e53, you can flash your MS43 ecu to the EU2 tune (without cats) and disable the rear o2 sensors, eliminate the CEL, and pick up a few added ponies and better responce/driving characteristics. You gotta run 91 octane like any performance tune, as the US tune is "adjusted" for possible lesser grade fuel to be used. I wish I could do this, as it's free if you have the goods to program, but not compatible with the newer ECU MS45 I've heard. This works with cats and you can go to a EU3 or 4 Flash perhaps for similar results. You have to research it out. I quit once I discovered that my ECU was a no go with the euro flash. Shark injector, here I come!

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2005 X5 3.0, 6MT, Alpine White on Truffle Brown, Sport, Preim, and Cold Weather, Alpina Stainless Headers, AFe Intake, UUC SSK, OEM 87's, 3.64 Differential Swap,Performance Modified Euro 2 Tune, UUC LTW Flywheel and HD clutch, Bilstein B12 Suspension kit
Future mods ZHP/Schrick Cam Shaft upgrade, Operation code name:Doppelschrauben-Kompressor

Wife's Ride: 2011 e70 X5 351 M///Sport.

Also in the fold: 2004 X3 3.0, 6MT, Black Sapphire on Terracotta, port, Premium, Cold Weather.